As an electrophotographic image forming apparatus, a color printer is known which includes four photosensitive drums for four colors, yellow, magenta, cyan, and black.
A color multifunction apparatus, which is proposed as an example of the color printer, may include process cartridges for each color, LED units, an intermediate transfer belt and a secondary transfer roller. The process cartridges may be arranged in tandem with each other horizontally. Each of the process cartridges may include a photosensitive drum and a developing unit. The developing unit may include a developing roller, a first supply roller, a second supply roller, a doctor blade, and a toner container. Each of the LED unit may be configured to expose a corresponding photosensitive drum from below. The intermediate transfer belt may extend horizontally such as to contact the photosensitive drums in the respective process cartridges from above. The secondary transfer roller may be disposed such as to contact the intermediate transfer belt from one horizontal direction.
In the above color multifunction apparatus, each LED unit may include an LED head uncovered.
As the LED head is uncovered, the LED head may get soiled by toner dropped from above or dust accumulated on the LED head.